Replying to Evolution

Ok, I've been reading this book by Richard Dawkins called The Ancestors Tale, and its one of the most thought provoking books I've ever read. Great book, even for non-biologists, I'd recommend everyone read a few chapters. He traces humanity back through generations and talks about species that join up as he takes us back through our lineage. Anyways, I digress.

One really cool idea I just came across: Gulls in the UK. There are two separate gull species that nest there, one with black wings, the other mostly white. They dont interbreed, and scientists have given them two different species names. One species proliferates westward, the other eastward. However, if you start sampling the gulls in either direction, the further you get away from the islands, the more grey they become... until around halfway across the globe, the two separate species both look very very similar, and in fact interbreed. Its like a spectrum, where each individual is able to interbreed in say, a westward direction... and it wraps around so far that by the time you reach the end of the spectrum, the individuals are separate species. Freaking crazy.

This can be applied to a broader range however. We really dont have separate species... ever. Its just that the 'links' between species have died out. For example, if some of the ancestoral apes that walked africa still existed, its reasonable to believe that members of our species could breed with them, and those could breed with others... until there was a chain of interbreeding that directly linked chimps to us. Humans and chimps could never interbreed, but through all the intermediates, we would cease to be separate species....

This is back to another idea as well. In the fossil record, we never really have distinct species. All we see are snapshots of an ever changing morphology. In fact, its good that we have gaps in our fossil record... if we didnt, and had the bones of every single species that ever lived, we would never see distinct species, just transitional forms. A cool analogy would be to think of evolution like a tea kettle. Theres never a point in the water where it goes from 'cold' to 'hot', yet it still boils. People need to stop thinking of evolution or speciation on the whole as specific and distinct.

Anyways, cool rant. Richard Dawkins is a great author, really thought provoking stuff. Check it out!